It is known from various U.S. patents, including: U.S. Pat. Nos. 3,782,947; 4,279,945; 5,217,804; 5,147,768; 5,229,259, and others; to include in a light-sensitive silver halide photographic element a transparent magnetic recording layer. Such elements are advantageous because they can be employed to record images by the customary photographic process while at the same time information can be recorded into and read from the magnetic recording layer by the techniques similar to those employed in the magnetic recording art.
The magnetic recording layers used in the magnetic recording industry, however, are usually opaque, not only because of the nature of the magnetic particles, but also because of the other additives required in the recording layer. For obvious reasons such opaque layers are not suitable for use with photographic elements. Further, the recording and reading requirements of the magnetic signal from a transparent magnetic layer present on a photographic element are more stringent those of a conventional magnetic recording because of the loading of the magnetic particles in the transparent magnetic layer and the nature of the photographic element. The magnetic recording layer of the photographic element must be capable of accurately recording the information applied thereto and reading out the information on demand. This is particularly difficult because the loading of the magnetic particles in the transparent layer must not interfere with the quality of the photographic elements.
The photographic element and particularly the transparent magnetic recording layer provided thereon must also be capable of repeated use in both the recording and reading mode and, therefore, must have improved running, durability, and head cleaning. For example, during the residence of the film in a camera, entries may be made to the magnetic recording layer for every exposure, and an indeterminate number of read operations are conducted depending on the particular application in which the film is used. This also is true in the processing of the film and in subsequent use of the processed film for additional copies, enlargements and the like. Also, because of the curl of the element, primarily due to the photographic layers and core set, the film must be held tightly against the magnetic heads by pressures much higher than those in conventional magnetic recording in order to maintain film plane flatness in the recording and reading zone. Finally, it is desirable that a transparent magnetic recording layer superposed on a backside of the support can be annealed at temperatures in excess of 80 deg. C. prior to emulsion coating without degrading physical properties or interfering with the quality of the photographic element.
Therefore, a need exists for a photographic element having a transparent magnetic recording layer exhibiting improved magnetic and photographic performance as well as improved running durability and head cleaning properties. All of these various characteristics must be considered both independently and cumulatively in order to arrive at a commercially viable photographic element.